In the case of a four-way stop, who must yield to a right-turning vehicle?

At a four-way stop, the vehicle turning left must yield to the vehicle that is turning right. This is primarily because the right-turning vehicle is making a maneuver that puts it in a more favorable position in terms of movement through the intersection. When two vehicles approach an intersection at the same time, the one that is turning left has a greater responsibility to ensure it does not conflict with other vehicles that are continuing straight or turning right. Thus, the right-turning vehicle has the right of way, and the left-turning vehicle must yield to them.

In the context of pedestrians and vehicles going straight, while they have their own rules and right-of-way considerations, the important aspect here focuses on the interaction between turning vehicles at a four-way stop. The vehicle that arrived last generally would not be an issue in this scenario since the established rules for yielding in left versus right turns take precedence.